Externally adjustable tubular fluid flow restrictor for refrigeration systems



Dec. 5, 1950 A F HO 2,532,452

ESEL EXTERNALLY ADJUSTABLE TUBULAR FLUID FLOW RESTRICTOR FORREFRIGERATION SYSTEMS Filed June 14, 1945 IN V EN TOR.

Patented Dec. 5, 1950 UNITED STATES PATENT m 2 1 EXTERNALLY ADJUSTABLETUBULAR FLUID FLOW RESTRICTOR FOR 1113- FRIGERATION SYSTEMS Anthony F.Hoesel, Chicago, 111., assignor, by mesne assignments, to AlbertWittlin, Chicago,

At present, most domestic mechanical refrigerators employ either anautomatic expansion valve or a capillary tube to maintain the necessarypressure differentials between the high pressure and low pressure sidesof the system.

For my purpose, we can disregard the operation with the automaticexpansion valve. One of the difficulties, of using a capillary tube forthe purpose, is that it practically has to be a laboratory determinedmethod and cannot be employed by an ordinary service man, in the field,except with a factory replacement for the particular unit.

Many systems would have the atuomatic expansion valve replaced with acapillary tube, if the service man would know exactly the correctcapillary tube bore size and correct length of capillary tube for theparticular job.

Since the presently employed capillary tubes depend upon a given lengthof uniform bore to produce the necessary flow restriction for themaintenance of the necessary pressure differentials, between thecondenser and the evaporator. there is no means for adjustment and thecorrect capillary tube, as factory determined, must be used on anyparticular job.

Strictly speaking, my invention does not contemplate a capillary tube,although it employs tubing of relatively small size in the practicethereof. Taking a system, which would ordinarily have a standardcapillary tube of say, .040" bore and, say, 36" length, I would have atube of, say, .060" bore and only about -6" length. In order to get anequivalent restrictor effect, I propose a rather novel means of makingthe bore adjustable, at some certain point or points, without the use ofvalves or other expensive means generally equipped with stuffing boxesor equivalents.

An object, of the present invention is to provide a novel means ofadjusting a tube bore in order to control a fiuid flow ratetherethrough.

Another object, of the present invention, is to provide an inexpensiveadjustable fiow restrictor for use with refrigeration systems.

Further objects, of the present invention, will be disclosed within thefollowing specification and claims.

In the drawings:

Fig. 1 is a view of a refrigerating system employing the invention.

Application June 14, 1945, Serial No. 599,489 zolaims. (01. 138-45) Fig.2 is a cross-sectional view of the flow restrictor; of Fig. 1. Y

Referring to the drawings: 1

In Fig. 1, a compartment 1 is cooled by means of a cooling coil 8 fromwhich-the compressor 9, driven by means not shown, evacuates refrigerantvapor by means of the suction conduit 10 connecting .therebetween. Thecompressor 9 compresses the vapor into the discharge conduit llleadingto a condenser I2 wherein the compressed vapor surrenders its heat andbecomes liquefied prior to its entry into the liquid conduit I3 leadingto the pressure restrictor I4, which discharges to the cooling coil 8. qa

In Fig. -2, the pressure restrictor l4 comprises two flared tube endfittings l6 and I1 between which, and in the bores l8 andl9, is placed atube 20 of copper, in the present instance, and having a bore 2|, whichis generally, initially, of uniform diameter. The tube 20 is soldered tothe end fittings I6 and I1, as indicated, at 22 and 23 respectively.

The tube bore adjusting means comprises a ferrule 21 having a diametraltaper toward each end thereof and an initial bore which is a slip fitover the tube 20.

The compression member 28 has a bore 29, which is-a slip fit over thetube 20, and a taper bore 30 somewhat similar to the diametral taper ofthe ferrule '21 engaging therewith.

The compression member has a bore 34, which is a slip fit over the tube20, and a taper bore somewhat similar to the diametral taper of theferrule 21 engaging therewith.

The compression member 21; has a threaded bore 31 engaging the malethread 38 of the compression member 33. Screwingjpp the compres sionmembers 28 and 33 resultfsffz in the respective tapers 30 and 35approaching each other and compressing the ferrule 21 therebetween. Thisreduces the initial bore, of the ferrule 21, and squeezes the outsidediameter, of the tube 20, at that point, whereby I now have a reducedboretn which is of diametral form.

Whenever a tube is so compressed, the tube wall thickness, at the pointof compression, is

materially increased; therefore, the original tube strength is onlyslightly disturbed.

Since the reduced bore is of diametral form, same as originally exceptreduced in size, it has the virtue of being able to pass foreign matterof many times the size which would clog up a needle valve, associatedwith a valve seat having a bore equivalent to the initial bore of thetube 20, ads justed to equivalent fluid flows.

Since the bore reduction is comparatively gradual, during the screwingup of the compression members, the proper size thereof is easilyattained.

Instead of soldering the tube 20, as at 23, I might combine the male.thread 38 and the taper 35 with theflared end fitting H, resulting in"decreased expense.

In effect, What I have done is to provide an ad,-

justment to regulate fluid flow through a. tube.

without the use of valves, etc.

While the invention is definitely adaptable to refrigeration systems, ithas a much Wider field of utility and I do not wish to'beconfinedthereto;

While the drawings show=and the specification explains a particularembodiment of the invention, it is to be understood thatvariousmodifiea-.

two inter-engaged threaded compression members'mounted on the tube atopposite ends of the ferrule and arranged to engage the same andcapableof compressing both the ferrule and the tube wall during wrench-up; sothat the tube bore may bev contracted; for controlling the flow rate ofthe volatile refrigerant fluid through the assembly.

2. For interposition in the liquid circuit of a refrigeration systemhaving an evaporator, a pressure restrictor comprising a tube ofcompressible metal having a potential refrigerant liquid flow rate inexcess of the vaporizing capacity of the evaporator, andcompressionmeans comprising a ferrule arranged on the tube between the endsthereof, said ferrule being oppositely tapered toward its ends, and twointerengaged threaded compression members slidably mounted on the tubeat opposite ends of the ferrule andhaving tapered portions arranged toengage the tapered portions of the ferrule and capable ofrelativeadjustment to compress the ferrule radially to reduce the size of theopening in the ferrule and compress the tube inwardly and reduce thediameter of the bore and simultaneously increase the wall thickness ofthe reduced portion of the tube.

ANTHONY F. I-IOESEL.

REFERENCE S CITED The following references are ofrecord in. the file ofthis patent:

